Climate change facts: the science and impacts

This warming is caused by a build-up of carbon dioxide and other greenhouse gases in our atmosphere.

The gases trap heat by forming a blanket around the Earth – like the glass of a greenhouse.

These gases stay in the atmosphere for many years. And as they build up, the planet’s temperature rises. A warmer world leads to a more extreme climate – with more severe droughts, floods and storms. And as the world warms up, feedback-loops can accelerate warming: melting polar ice means less of the sun’s heat is reflected back into space.

Greenhouse gases build up in the atmosphere mainly due to the burning of fossil fuels – coal, oil and gas – and by cutting down forests. Greenhouse-gas levels have rocketed in the last 100 years.

The Paris Agreement calls for “global emissions peaking as soon as possible, and rapid reductions thereafter”.

Two of the biggest solutions are being far more efficient in how we use energy, and moving from coal, oil and gas to 100% renewable energy as fast as possible.

The good news is that this is starting to happen, and is accelerating fast. Renewable electricity costs have plummeted in the last few years, and the amount of wind and solar power is rocketing, all over the world.

The task is urgent – it is what happens between now and 2030 that overwhelmingly determines whether we can keep to 1.5°C, and save as many lives and livelihoods as possible.

Change needs to happen quickly. But it has to be done in a fair way. Rich countries like the UK must lead the way. We are far more responsible for the global climate change we see today – our economy has been built on exploiting coal, oil and gas. Rich countries also have a responsibility to help poorer countries adapt to climate change, and cope with impacts we can no longer avoid.